diff options
| -rw-r--r-- | arch/loongarch/kvm/timer.c | 68 |
1 files changed, 55 insertions, 13 deletions
diff --git a/arch/loongarch/kvm/timer.c b/arch/loongarch/kvm/timer.c index d362d87a54aa..111328f60872 100644 --- a/arch/loongarch/kvm/timer.c +++ b/arch/loongarch/kvm/timer.c @@ -69,14 +69,19 @@ void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long timer_hz) */ void kvm_restore_timer(struct kvm_vcpu *vcpu) { - unsigned long cfg, delta, period; + unsigned long cfg, estat; + unsigned long ticks, delta, period; ktime_t expire, now; struct loongarch_csrs *csr = vcpu->arch.csr; /* * Set guest stable timer cfg csr + * Disable timer before restore estat CSR register, avoid to + * get invalid timer interrupt for old timer cfg */ cfg = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TCFG); + + write_gcsr_timercfg(0); kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_ESTAT); kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_TCFG); if (!(cfg & CSR_TCFG_EN)) { @@ -91,19 +96,46 @@ void kvm_restore_timer(struct kvm_vcpu *vcpu) hrtimer_cancel(&vcpu->arch.swtimer); /* + * From LoongArch Reference Manual Volume 1 Chapter 7.6.2 + * If oneshot timer is fired, CSR TVAL will be -1, there are two + * conditions: + * 1) timer is fired during exiting to host + * 2) timer is fired and vm is doing timer irq, and then exiting to + * host. Host should not inject timer irq to avoid spurious + * timer interrupt again + */ + ticks = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TVAL); + estat = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_ESTAT); + if (!(cfg & CSR_TCFG_PERIOD) && (ticks > cfg)) { + /* + * Writing 0 to LOONGARCH_CSR_TVAL will inject timer irq + * and set CSR TVAL with -1 + */ + write_gcsr_timertick(0); + + /* + * Writing CSR_TINTCLR_TI to LOONGARCH_CSR_TINTCLR will clear + * timer interrupt, and CSR TVAL keeps unchanged with -1, it + * avoids spurious timer interrupt + */ + if (!(estat & CPU_TIMER)) + gcsr_write(CSR_TINTCLR_TI, LOONGARCH_CSR_TINTCLR); + return; + } + + /* * Set remainder tick value if not expired */ + delta = 0; now = ktime_get(); expire = vcpu->arch.expire; if (ktime_before(now, expire)) delta = ktime_to_tick(vcpu, ktime_sub(expire, now)); - else { - if (cfg & CSR_TCFG_PERIOD) { - period = cfg & CSR_TCFG_VAL; - delta = ktime_to_tick(vcpu, ktime_sub(now, expire)); - delta = period - (delta % period); - } else - delta = 0; + else if (cfg & CSR_TCFG_PERIOD) { + period = cfg & CSR_TCFG_VAL; + delta = ktime_to_tick(vcpu, ktime_sub(now, expire)); + delta = period - (delta % period); + /* * Inject timer here though sw timer should inject timer * interrupt async already, since sw timer may be cancelled @@ -122,15 +154,25 @@ void kvm_restore_timer(struct kvm_vcpu *vcpu) */ static void _kvm_save_timer(struct kvm_vcpu *vcpu) { - unsigned long ticks, delta; + unsigned long ticks, delta, cfg; ktime_t expire; struct loongarch_csrs *csr = vcpu->arch.csr; + cfg = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TCFG); ticks = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TVAL); - delta = tick_to_ns(vcpu, ticks); - expire = ktime_add_ns(ktime_get(), delta); - vcpu->arch.expire = expire; - if (ticks) { + + /* + * From LoongArch Reference Manual Volume 1 Chapter 7.6.2 + * If period timer is fired, CSR TVAL will be reloaded from CSR TCFG + * If oneshot timer is fired, CSR TVAL will be -1 + * Here judge one-shot timer fired by checking whether TVAL is larger + * than TCFG + */ + if (ticks < cfg) { + delta = tick_to_ns(vcpu, ticks); + expire = ktime_add_ns(ktime_get(), delta); + vcpu->arch.expire = expire; + /* * HRTIMER_MODE_PINNED is suggested since vcpu may run in * the same physical cpu in next time |